"It was quite strange, quite strange request," Lookyanov said. But he said Hansen wrote to him that Russian officials would be waiting for the boy at the ministry.

Lookyanov picked up Saveliev on Thursday, April 8. He said the boy was the first out the doors in the arrival hall, because he had no luggage.

Upon arrival at the ministry, Lookyanov said he informed a police guard about the arrival of Artyem Saveliev.

"The police stared at us like a crazy man," Lookyanov said. "And at this moment my heart was broke... it was the first stroke for me, realizing something was going wrong."

Lookyanov and ministry officials found a letter Saveliev was carrying. Addressed to the Ministry of Education and signed by Saveliev's adoptive mother Torry, it declared "I no longer wish to parent this child. As he is a Russian National, I am returning him to your guardianship and would like the adoption disannulled [sic]."

"I was shocked, I felt misled," Lookyanov said. He then called Nancy Hansen from his cell phone.

"At first it was silent. About half a minute. And then she responded," the driver said. "She started to tell about the life, about this boy. About his mental health."

The Hansen family told CNN Saveliev had mental problems and that he was dangerous -- accusations Russian officials have denied.

The Russian government has taken Saveliev into custody.

On Thursday, the Kremlin announced it would freeze new American adoptions of Russian children until both governments sign a bilateral agreement regulating adoption.

This was not the first time Lookyanov stumbled across a disastrous international adoption, he said.

Several years ago, he said he was hired by an American couple by the last name of Pavlis.

"They just wanted to see some sites," Lookyanov recalled. "They also asked me to drive them to a hospital to pass an adoption examination for their boy."

Lookyanov said he spent two days working with Irma and Dino Pavlis. He said he took them and their adopted Russian son Alex to McDonald's and ate with them.

"Two months after I saw them in Moscow... I learned that by accident this boy died," Lookyanov said.

A month after the adoption, six-year old Alex was dead due to blunt force trauma to the head, news reports at the time said. There was evidence that his adoptive mother had punched him in the stomach.

A court sentenced Irma Pavlis to 12 years in prison for manslaughter. She reportedly served five.

Lookyanov's brushes with failed adoptions have left him reeling, physically shaking as he discussed the cases.

"Now you can understand how I was shocked, like a double shock," he said.

"I know lots of friends in America and they take care of their kids like angels," he added. "Thousands of kids were adopted. [But] I understand there has to be some more control."

Lookyanov now says that in the future, he may ask more questions before accepting a job with a new client.